U.S. patent number 4,166,260 [Application Number 05/891,236] was granted by the patent office on 1979-08-28 for circuit breaker accessory assembly.
This patent grant is currently assigned to General Electric Company. Invention is credited to Stephen F. Gillette.
United States Patent |
4,166,260 |
Gillette |
August 28, 1979 |
Circuit breaker accessory assembly
Abstract
A circuit breaker accessory assembly, such as a shunt trip
solenoid, is affixed to an insulative mounting member which is
interchangeably mounted in place of a conventional interphase
barrier within the breaker molded case. The trip solenoid plunger
is operatively coupled with the breaker common trip bar, while the
actuator for a normally closed switch wired in the solenoid
energization circuit is positionally mounted for actuation by
movement of a breaker contact arm to its open circuit position,
thereby opening the switch.
Inventors: |
Gillette; Stephen F. (Hartford,
CT) |
Assignee: |
General Electric Company (New
York, NY)
|
Family
ID: |
25397836 |
Appl.
No.: |
05/891,236 |
Filed: |
March 29, 1978 |
Current U.S.
Class: |
335/20;
335/202 |
Current CPC
Class: |
H01H
83/20 (20130101); H01H 71/0228 (20130101) |
Current International
Class: |
H01H
71/02 (20060101); H01H 83/00 (20060101); H01H
83/20 (20060101); H01H 073/06 (); H01H
073/08 () |
Field of
Search: |
;335/20,8,9,10,202
;200/333,338 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Broome; Harold
Attorney, Agent or Firm: Cahill; Robert A. Bernkopf; Walter
C. Schlamp; Philip L.
Claims
Having described my invention, what I claim as new and desire to
secure by Letters Patent is:
1. In a multipole circuit breaker having a molded case consisting
of a base and a cover having complimenting intermediate partitions
serving to provide interphase isolation between adjacent pole
chambers, at least the intermediate base partitions being provided
with interruptions accommodating the transverse extension of a
movable contact arm uniting cross bar, the edges of the base
partitions bounding the interruptions being provided with grooves
for slidingly receiving insulative barriers in non-interfering
relation with the cross bar to substantially restore interphase
isolation between adjacent pole chambers, an accessory assembly
comprising, in combination:
A. an insulative mounting member having
(1) a panel-like section of equivalent size to the interphase
barrier for sliding receipt in lieu thereof in the grooves of one
base partition interruption, and
(2) an integral upstanding mounting flange;
B. an accessory apparatus; and
C. fastening means for securing said accessory apparatus to said
mounting flange in operative position within one of the breaker
pole chambers.
2. The accessory assembly defined in claim 1, wherein said mounting
member is structured to accommodate engagement by the complimenting
one of the cover intermediate partitions, whereby said mounting
member is clamped in place when the cover is secured in case
closure relation with the base.
3. The accessory assembly defined in claim 1, wherein said mounting
flange is laterally offset from said panel section to provide a
shoulder accommodating engagement by the complimenting one of the
cover intermediate partitions, whereby said mounting member is
clamped in place when the cover is secured in case closure relation
with the base.
4. The accessory assembly defined in claim 3, wherein said mounting
member further includes webs molded on said shoulder, said webs
being sized so as to readily plastically deform in response to
clamping engagement by the complimenting intermediate cover
partition.
5. The accessory assembly defined in claim 3, wherein said
accessory apparatus includes a solenoid having a plunger
operatively coupled with a breaker common trip bar.
6. The accessory assembly defined in claim 5, wherein said mounting
member includes internal reinforcing ribs interconnecting said
panel section and mounting flange on the opposite side from said
shoulder.
7. The accessory assembly defined in claim 6, wherein said ribs
extend laterally beyond said mounting flange to provide ledges on
which a portion of said solenoid rests.
8. The accessory assembly defined in claim 7, wherein said solenoid
is a shunt trip solenoid, said accessory apparatus further
including a normally closed switch wired into an electrical lead
into one side of the activating coil for said shunt trip solenoid
and an actuating arm positioned to be deflected by a breaker
movable contact arm in moving to its open circuit position, said
deflected actuating arm actuating said switch to its open
condition.
9. The accessory assembly defined in claim 8, wherein said mounting
member further includes webs molded on said shoulder, said webs
being sized so as to readily plastically deform in response to
clamping engagement by the complimenting intermediate cover
partition.
10. The accessory assembly defined in claim 9, wherein said
fastening means is a single screw.
Description
BACKGROUND OF THE INVENTION
Users of industrial molded case circuit breakers are increasingly
demanding that additional functions over and above traditional
overcurrent circuit protection be incorporated in the circuit
breakers. To meet this demand, manufacturers have developed a line
of accessory devices, such as shunt trips, undervoltage releases,
bell alarms, lockouts, etc., for incorporation in their circuit
breakers. While these accessory devices are relatively simple in
design, it is often quite difficult to package these devices within
the breaker case, principally because of space limitations and
assembly difficulties. This is particularly so in the smaller
breaker frame sizes. As a consequence, it is not uncommon to find
industrial molded case circuit breakers being assembled on
virtually a shop order basis when they are to be equipped with one
or more accessory functions.
It is accordingly an object of the present invention to provide
improved mounting provisions for physically and operationally
incorporating an accessory function within the molded case of a
multi-pole circuit breaker.
An additional object is to provide improved accessory mounting
provisions of the above character, wherein an accessory device can
be readily mounted within a circuit breaker case in a simple and
expeditious manner.
Yet another object is to provide an improved accessory assembly
which does not require special or additional fastening elements in
mounting the accessory assembly within a breaker case.
A further object of the present invention is to provide a circuit
breaker accessory assembly capable of being retrofitted in an "off
the shelf" molded case circuit breaker in a simple and economical
fashion.
Other objects of the invention will in part be obvious and in part
appear hereinafter.
SUMMARY OF THE INVENTION
In accordance with the present invention, a circuit breaker
accessory device is affixed to an insulative mounting member which
is structured to be interchangeably mounted within a molded circuit
breaker case in place of a conventional, removable interphase
barrier. The mounting member thus serves not only to mount the
accessory device, but also to afford the requisite breaker
interphase isolation normally provided by the removed barrier. The
mounting member is captured by lateral edge engaging grooves
provided in an interphase partition molded into the base of the
breaker case in the same manner as the normal interphase barrier
and is clamped in place by the cover of the breaker case.
In the specifically disclosed embodiment of the invention, the
accessory device is illustrated as a shunt trip solenoid. A
suitable fastener, such as a screw, engages the solenoid frame to
assemble the shunt trip solenoid to the mounting member. The
resulting assembly is then mounted within the breaker case with the
solenoid plunger operatively coupled with the breaker common trip
bar. This assembly also includes a normally closed switch mounted
to the solenoid frame and wired in series with one of the solenoid
coil leads. An actuator arm for this switch is mounted to the
assembly so as to be positioned for engagement by a breaker contact
arm as it moves to its open circuit position, thereby opening the
switch and the solenoid energization circuit.
The invention accordingly comprises the features of construction
and arrangement of parts which will be exemplified in the
construction hereinafter set forth, and the scope of the invention
will be indicated in the claims.
For a better understanding of the nature and objects of the
invention, reference should be had to the following detailed
desscription taken in conjunction with the accompanying drawings,
in which:
FIG. 1 is a plan view, partially broken away, of a three-pole
molded case circuit breaker incorporating the accessory assembly of
the present invention;
FIG. 2 is an exploded, fragmentary perspective view illustrating
the manner in which the accessory assembly is mounted within the
circuit breaker of FIG. 1;
FIG. 3 is a front elevational view, partially in section, of the
mounted accessory assembly of FIG. 2 with the cover of the breaker
case displaced from its case closure position;
FIG. 4 is a front elevational view, partially in section, of the
mounted accessory assembly of FIG. 2 with the case cover secured in
its case closure position;
FIG. 5 is a fragmentary, side elevational view of the mounted
accessory assembly of FIG. 2, illustrating its quiescent condition;
and
FIG. 6 is a fragmentary, side elevational view of the accessory
assembly of FIG. 2, illustrated in its operated condition.
Like reference numerals refer to corresponding parts throughout the
several views of the drawings.
DETAILED DESCRIPTION
The accessory assembly of the present invention, generally
indicated at 10, is illustrated in FIG. 1 as being incorporated in
a three-pole electric circuit breaker, generally indicated at 12,
which may be of the construction disclosed in U.S. Pat. No.
3,309,479. The circuit breaker includes a molded insulative case,
generally indicated at 14, comprising a cover 16 and a base 18
secured together by a plurality of screws 19. Sidewalls of the base
and cover, together with a pair of intermediate partitions
upstanding from the base (one seen at 20), define three separate,
side-by-side breaker pole chambers. The cover is provided with
depending intermediate partitions, one seen at 22 in FIGS. 3 and 4,
which cooperate with the base intermediate partitions 20 in
substantially totally partitioning the pole chambers to provide
effective interphase isolation.
Each pole chamber accommodates a stationary contact 24 affixed to a
terminal strap 26 anchored to the floor 18a of base 18, all as seen
in FIGS. 5 and 6. Operating in each pole chamber is an arm 28 which
mounts a movable contact 30. Each arm is mounted by a pivotal
carrier 32 for movement of its movable contact 30 into and out of
engagement with stationary contact 24. Movement of the arms is
motivated in unison by an operating mechanism (not shown)
accommodated in the center pole chamber and acting via a cross bar
34 tying the carriers 32 in the three-pole chambers together. To
accommodate the assembly and transverse extension of cross bar 34
through the three-pole chambers, the intermediate partitions 20
upstanding from base 18 are provided with an interruption 36, best
seen in FIG. 2. Also spanning the three-pole chambers is a
rotatably mounted common trip bar 38 which carries a centrally
located latch 38a for normally latchably engaging a trigger 40 to
sustain the breaker operating mechanism in its reset or untripped
condition. The common trip bar also carries a series of upstanding
flanges 38b for separate disposition in each of the breaker pole
chambers. These flanges provide flat surfaces against which
conventional overcurrent responsive, thermal-magnetic trip elements
can act to rotate the trip bar, thereby releasing the trigger 40 to
trip the breaker in response to a current flow of overcurrent
proportions through any one of the breaker poles. As seen in FIG.
2, the interruptions 36 in the intermediate base partitions 20 are
relieved, as indicated at 36a, so as to accommodate the transverse
extension of common trip bar 38.
To substantially restore the loss of interphase isolation caused by
the interruption 36 in each intermediate base partitions 20, a
planar, insulative barrier is slideably received in grooves 36b
formed in the edges of the base partitions bounding the
interruption. These barriers are then captured in place by the
depending cover partitions 22 when cover 16 is secured in closure
relation with base 18. It is a signal feature of the present
invention to replace one of these interphase barriers with a
uniquely structured, insulative member, generally indicated at 50,
which, in addition to serving as an interphase barrier,
accommodates the mounting of accessory assembly 10 in a requisite
operational position. Thus to physically adapt circuit breaker 12
with the accessorial function provided by accessory assembly 10,
one has only to slide mounting member 50 down into grooves 36b in
place of the normal interphase barrier.
By way of example, accessory assembly 10 is disclosed as comprising
the requisite components for providing a shunt trip function.
However, it will be appreciated that mounting member can be readily
modified to mount a variety of components pursuant to providing
other accessorial functions, such as undervoltage release,
auxiliary switching, etc. As seen in the drawings, mounting member
50 is provided with a panel-like section 52 of equivalent size to
the normal interphase barrier so as to provide equivalent
interphase isolation when slid down into grooves 36b formed in base
partition 20. Upstanding in laterally offset fashion from panel
section 52 is a flange 54 having a hole for accommodating a screw
55 whose shank is threaded into a tapped bore provided in the frame
56 of a shunt trip solenoid 58. To provide structural integrity,
several triangular-shaped ribs 60, are molded into mounting member
50 between panel section 52 and flange 54. Preferably, these ribs
extend laterally beyond flange 54 so as to provide ledges 60a
(FIGS. 3 and 4) on which the lower edge of solenoid frame 56 rests.
These ledges, together with screw 55, serve to securely mount shunt
trip solenoid 58 to mounting member 50 in anti-turn fashion.
The lateral offset relation of flange 54 to panel section 52
creates a shoulder 62 against which the depending intermediate
cover partition 22 bears when cover 16 is secured in closure
relation with base 18 (FIGS. 3 and 4). To accommodate manufacturing
tolerances, small triangular-shaped webs 62a are molded into
shoulder 62 in positions to be engaged by cover partition 22. These
webs plastically deform in response to the press of cover partition
22 as the cover screws 19 are tightened down (FIG. 4), thereby
insuring positive clamping pressure on mounting member 50 when the
cover 16 is tightly secured to base 18.
Solenoid 58 is equipped with a plunger 64 having affixed to its
outer end a clip 66 structured to partially embrace the particular
flange 38b of common trip bar 38 situated in the same pole chamber
with accessory assembly 10. It is seen from FIGS. 5 and 6 that upon
energization of solenoid 58, its plunger is attracted or pulled in,
causing common trip bar 38 to be rotated in a direction to
disengage its latch 38a from trigger 40, and the breaker trips. A
compression spring 68 normally biases plunger 64 to its extended
position, thereby permitting the trip bar latch 38a to engage
trigger 40. This spring is sufficiently light so as not to impede
the action of any of the thermal-magnetic tripping elements on the
common trip bar.
It is common practice to wire the trip solenoid coil through a
normally closed switch which is opened in response to the opening
of the breaker to interrupt the solenoid energization circuit and
thus preclude needless solenoid energization. Under these
circumstances, the shunt trip solenoid can be inexpensively
designed for only very limited duty. To this end, a normally closed
switch 70, best seen in FIGS. 2, 5 and 6, is mounted to the
solenoid frame 56 by a pair of small screws 72. One lead 74 is
wired through this switch to one side of the solenoid coil. Screws
72 also serve to mount a resilient actuator arm 76 which depends
down into the pole chamber to a termination poised in closely
spaced relation to the movable contact arm 28 therein while it is
in its closed circuit position (FIG. 5). When the breaker is
manually opened or tripped open, either by the shunt trip solenoid
or by the thermal-magnetic tripping elements, contact arm 28 is
swung upwardly into deflecting engagement with actuator arm 76.
This deflection causes arm 76 to engage an actuator button 70a,
transferring switch 70 to its open condition. It will be noted that
switch 70 is sustained in its open condition as long as the breaker
contacts are open to thus inhibit needless energization of the
shunt trip solenoid.
It will thus be seen that the objects set forth above, among those
made apparent in the preceding description, are efficiently
attained and, since certain changes may be made in the above
construction without departing from the scope of the invention, it
is intended that all matter contained in the above description or
shown in the accompanying drawings shall be interpreted as
illustrative and not in a limiting sense.
* * * * *